Many electric four-wheel vehicles exist for transportation of people or goods, as well as for recreational use. Electric vehicles designed for use in the sport of golf are the most common of these vehicles, although electric adaptive vehicles for physically challenged persons are also popular.
Electric four-wheel vehicles typically use series wound, separately excited DC induction motors that turn ring and planetary differential gears. The ring and planetary differential gears, in turn, rotate drive axles that are connected to pneumatic tire wheels to propel the vehicles. Although these vehicles are designed to transport people, some goods can also be transported.
Electric four-wheel vehicles typically use a two-wheel, spring-based transverse beam for the front suspension, and low-pressure high flotation pneumatic tires. Braking is mechanically activated using drum type friction brakes on the rear wheels. Positive override parking brakes are usually an integral part of the mechanical brake system.
A constant 24/36/48 volts is provided to the DC motors from storage batteries with the electrical current input controlled by fixed amperage controllers. The storage batteries are recharged by separate 110 or 220 volt chargers. A potentiometer provides varying amounts of current to the motors to throttle the vehicles.
The existing electric vehicles described above, however, are complicated contraptions. Thus, there is a continuing need to simplify the complicated drive and braking systems of existing electric four-wheel vehicles to make them mechanically stronger and reduce unnecessary maintenance.